Meanwhile, British troops say they killed nine suspected Taleban insurgents in neighboring Helmand province. They say they used high explosives to overwhelm the insurgents after spotting them preparing to attack.

In eastern Khost province, Afghan and U.S.-led coalition forces say they captured three suspected al-Qaida militants during a pre-dawn raid and confiscated weapons and ammunition.

Also Tuesday, the U.S.-led coalition said several rockets fired by suspected Taleban insurgents struck a nomad camp in the city of Gardez in eastern Paktia province, injuring two civilians.

Violence has escalated in recent weeks since NATO forces moved to southern Afghanistan to destroy suspected Taleban hideouts.